Research object of the thesis is polymer-nanostructured carbon composite (PNCC) and it’s capability to sense the presence of volatile organic compounds (VOC), that is, the composite electrical resitance increases greatly, when VOC are present. Review of scientific literature contains description of necessity to detect VOC in different fields of specialization like chemical production, air quality control, agricalture, food production and medicine. Information regarding possible kinds of chemical sensor materials for VOC detection are summerized and working principle of them described. Fundamentals of classical percolation and electrical percolation in polymer composites are discussed. Analyze of scientific literature evidence, that there is a luck of explanation about VOC induced electrical resistance change mechanism in polymer composite. Therefore one of the main goal of the thesis is to find out electrical resistance change mechanism of polymer composite, when VOC are present. Methodological part of the thesis contains charictarization of utilized materials (matrix and electroconducting filler) and detailed description of production technology as well. Originally elaborated setup and measuring technique for in-situ electrical resistance, mass and lenght change measurements of the PNCC samples at presence of VOC is presented. Firstly, technology of production and used materials (matrix and filler) impact on electrical precolation and electroconductive structure build by filler in the composite are evaluated in the experimental part of the thesis. VOC sensor effect, reversibility and repeatability of PNCC is estimated. Secondly, PNCC fundamental of electrical resistance change mechanism in the presence of chemical vapour is clarified by realizing in-situ electrical resistance, mass and length change measurements. 3 different electrical resistance change mechanisms are found to exsist in the PNCC, which depend on electroconductive structure of the composite, degree of swelling in the presence of VOC and electrical characteristis of VOC itself. Full amount of thesis are 160 pages.